Salar de Uyuni (or Salar de Tunupa) is the world's largest salt flat at 10,582 square kilometers (4,086 sq mi). It is located in the Potosí and Oruro departments in southwest Bolivia, near the crest of the Andes, and is elevated 3,656 meters (11,995 ft) above mean sea level. The Salar was formed as a result of transformations between several prehistoric lakes. It is covered by a few meters of salt crust, which has an extraordinary flatness with the average altitude variations within one meter over the entire area of the Salar.

A visitor relaxes in a sleeping module at Tokyo's tube Hotel “Capsule Inn Akihabara” on February 6, 2007 in Tokyo, Japan. The two-square-meter sleep modules are equipped with a TV, Radio and Wireless LAN and are priced at 3500 yen per night. Uptil recently it has mainly been the office workers who stay at such tube hotels when they cannot go home, but recently they are attracting many foreign travellers due to their Japanese style. (Photo by Koichi Kamoshida/Getty Images)

A visitor poses inside a three story upside-down family sized house at the Huashan Creative Park in Taipei, Taiwan April 7, 2016. Over 300 square meters of floor space of the upside-down house, filled with home furnishings, was created by a group of Taiwanese architects at a total cost of around US$600,000 and took 2 months to complete, according to the organisers. (Photo by Tyrone Siu/Reuters)

Activists and supporters of Ukrainian nationalist groups light flares during a rally to mark the third anniversary of the Euromaidan Revolution in downtown Kiev, Ukraine, 21 November 2016. About one thousand activists took park in the rally during which they burned tires on the Independence Square, destroyed the Russian bank Sberbank and broke windows in the office of a Ukrainian politician Viktor Medvedchuk, according to Ukrainian media. (Photo by Roman Pilipey/EPA)

Yakutsk, a remote city in Eastern Siberia along the Lena River, is the coldest city in the world. Located 1840 km away from Irkoustk and 5000 km away from Moscow, this city founded in 1632 by the Cossacks imposes upon its inhabitants an extreme way of life. And yet, despite particularly harsh conditions, Yakutsk boasts a population of 270,000, or a quarter of the entire population of Siberia. No other place on the planet experiences the temperature extreme found here: in winter, the temperatures regularly fall to minus 40° (the coldest temperature recorded was –64°C) and in summer often reaches temperatures above 30°C. Photo: January 2013. A scene in Yakutsk, Siberia, the coldest city in the world. (Photo by Steeve Iuncker/Agence VU)

A couple hugs while standing near a Christmas tree made out of plastic bins and plastic hampers outside the Museum of History in Monterrey, Mexico, December 4, 2015. The humble Christmas tree has a rich history, from evergreen trees used to symbolise eternal life in Ancient Egypt to tree worship among pagan Europeans. The modern version has its origins in Germany, where the song “O Tannenbaum” is still a festive favourite. Today the traditional tree with lights and decorations appears in cities including Washington, Moscow and Beirut. Alternative constructions range from recycled rubbish in Mexico City to old window frames in Rakvere, Estonia. Whatever the shape or size, the message is the same: Merry Christmas. (Photo by Neil Hall/Reuters)

Members of an electoral commission destroy unused ballots, after polling stations closed on the final day of the presidential election in Saint Petersburg, Russia on March 17, 2024. (Photo by Anton Vaganov/Reuters)

United States Marines perform a fighting demonstration in Times Square as part of Fleet Week festivities May 27, 2011 in New York City. Fleet Week, which has been held in New York since 1984, brings thousands of military members to the city where they engage the public with numerous activities, demonstrations, tours and contests. Fleet Week concludes on Memorial Day with a military flyover to honor those killed while serving in the military. (Photo by Spencer Platt/Getty Images)